The present invention relates to antiperspirant material-containing, solid gel stick compositions, and methods of making such compositions. In particular, the present invention is directed to clear, antiperspirant material-containing solid gel stick compositions, gelled by dibenzylidene sorbitol, and methods of making such stick compositions. More particularly, the present invention is directed to a clear antiperspirant solid gel stick composition containing an acidic antiperspirant active agent (for example, an acidic astringent metallic salt, such as an astringent aluminum salt) in the presence of dibenzylidene sorbitol as a gelling agent, the composition being stable, over extended periods of time, against deterioration of the gel (and being stable against deterioration of the gelling agent), and methods of making the same.
While dibenzylidene sorbitols are stable in alkaline or neutral media, such compounds are not stable in acidic media. In an acidic environment, such as in the presence of acidic antiperspirant materials, and when in the presence of even small amounts of water, the dibenzylidene sorbitol deteriorates and breaks down. Accordingly, there is a need to find a way to stabilize the sticks containing acidic antiperspirant material, and gelled with dibenzylidene sorbitol, against such deterioration.
U.S. Pat. No. 4,518,582 to Schamper, et al discloses an antiperspirant stick composition containing dibenzyl monosorbitol acetal in the presence of acidic antiperspirant-active salts, which composition is stable for extended periods of time at elevated temperatures. The composition contains at least a reactive solvent (such as water, methanol, ethanol, n-propanol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, etc.), dibenzyl monosorbitol acetal, an antiperspirant-active compound, and a gel stabilizer, the gel stabilizer being a member of a group consisting of magnesium sulphate, zinc acetate and hexamethylenetetramine and mixtures thereof. This patent discloses that the stabilizer prevents or retards deterioration of the gelled sticks, especially when exposed to elevated temperatures.
Another patent disclosing stabilizers for solid gel antiperspirant sticks containing an acidic antiperspirant-active compound in the presence of dibenzyl monosorbitol acetal is U.S. Pat. No. 4,719,102 to Randhawa, et al. This patent discloses that the sticks include a solvent which is a small, polar organic compound (suitable compounds fitting within this class being cyclic esters, amides, amines, ketones, ureas, carbamates, sulfoxides and sulfones, and their open chain analogs); a cosolvent (such as primary or low molecular weight alcohols, including ethanol, n-propanol, 1,2-propylene glycol, diethylene glycol, etc., and mixtures thereof); dibenzyl monosorbitol acetal; an antiperspirant-active compound; and a gel stabilizer, the gel stabilizer being a member of a group consisting of N-(2-hydroxyethyl) fatty (C.sub.8 -C.sub.20) acid amides, magnesium sulfate, zinc acetate, acetamide monoethanol amine and hexamethylenetetramine, and mixtures thereof.
U.S. Pat. No. 4,722,835 to Schamper, et al also discloses antiperspirant gel stick compositions gelled with dibenzyl monosorbitol acetal and containing an acidic antiperspirant compound, and also containing a stabilizer for the gel. This patent teaches that the compositions include a solvent which is a small, polar organic compound, as discussed previously in connection with U.S. Pat. No. 4,719,102; dibenzyl monosorbitol acetal; an antiperspirant-active compound; and the gel stabilizer, such gel stabilizer being a basic metallic salt (such as zinc oxide, calcium acetate, magnesium oxide, calcium carbonate, calcium hydroxide, magnesium carbonate, sodium carbonate, zinc carbonate and potassium carbonate). This patent discloses that these basic metallic salt gel stabilizers can stabilize the gel, even at high temperatures, even when propylene carbonate or butyrolactone are used as solvents.
Other patent documents disclosing antiperspirant sticks gelled with a dibenzylidene sorbitol and including stabilizers for the gel are European Patent Application (EPA) No. 451,002A2; European Patent Application (EPA) No. 512,770A1; and World Intellectual Property Organization International Published Application (PCT) No. WO92/19221.
EPA No. 451,002A2 discloses a stable, substantially anhydrous and substantially lower monohydric alcohol free, transparent, gelled, antiperspirant composition gelled by dibenzylidene monosorbitol acetal, containing acidic antiperspirants, and utilizing dihydric alcohols containing 3 to 6 carbon atoms as solvents, with the acetal being stabilized against hydrolysis and the formation of benzaldehyde by the presence of a stabilizing amount of a selected organic base, the organic base being a weakly basic, nitrogen-containing, organic compound. Preferred organic bases are urea; imidazole; 2-amino-2-hydroxymethyl-1,3-propanediol (Tris buffer); 2-amino-2-methyl-1-propanol; and N, N-tetrakis-2-hydroxypropyl ethylene diamine. This patent document discloses that strong bases which form compositions having a pH higher than 5 tend to precipitate the antiperspirant when attempts are made to employ them in the preparation of transparent antiperspirant sticks. The contents of EPA No. 451,002A2 are incorporated herein by reference in their entirety.
EPA No. 512,770A1 discloses a stable, substantially anhydrous and substantially lower aliphatic monohydroxy alcohol free cosmetic composition gelled by dibenzylidene monosorbitol acetal, and containing acidic antiperspirant compounds and utilizing dihydroxy aliphatic alcohols containing 3-6 carbon atoms as solvents, wherein the dibenzylidene monosorbitol acetal gelling agent is stabilized against hydrolysis and the formation of benzaldehyde by the presence of a stabilizing amount of a selected inorganic base, the inorganic base including alkali and alkaline earth metal oxides, hydroxides, carbonates or bicarbonates, and trivalent metallic hydroxides. Specific inorganic bases include sodium and potassium hydroxides, carbonates and bicarbonates as well as calcium and magnesium oxides, hydroxides and carbonates, aluminum hydroxide and aluminum magnesium hydroxide (provided these bases are soluble in the composition). This patent document further discloses that the decomposition of the gelling agent to benzaldehyde, which imparts an undesirable odor or color, may be further inhibited by adding a compound which will react with the benzaldehyde to produce a colorless and substantially odorless product. Such benzaldehyde scavenger includes polyhydroxy aliphatic polyhydric alcohols, such as glycerin.
PCT No. WO92/19221 discloses solid antiperspirant compositions in gel stick form, having an acid pH, and including (1) an antiperspirant active; (2) a gelling agent selected from the group consisting of substituted and unsubstituted dibenzylidene alditols; (3) a solvent for the gelling agent, preferably including a solvent material selected from the group consisting of monohydric and polyhydric alcohols, and mixtures thereof; and (4) a gelling agent stabilizer, the stabilizer being a basic metallic salt of an acid having a pKa of from about 3.8 to about 6.5 at 25.degree. C., the salt being at least partially soluble in the composition and being selected from the group consisting of C.sub.4 -C.sub.6 dicarboxylate salts, C.sub.6 -C.sub.8 monocarboxylate salts, and substituted or unsubstituted benzoate salts, and Mixtures thereof, the gelling agent stabilizer not containing amino or amido functionalities. This patent document teaches that for clear or translucent sticks, the gelling agent stabilizer present in the composition should be fully soluble in the composition, in order to minimize refraction of light.
The foregoing patent documents also disclose methods for forming the disclosed antiperspirant stick compositions containing the antiperspirant materials and gelling agent. In particular, attention is directed to U.S. Pat. Nos. 4,719,102 and 4,722,835. Each of these patents discloses processes of forming the stick compositions, including dissolving the antiperspirant active in one phase and the dibenzyl monosorbitol acetal gellant in another phase. The two phases are then combined and poured into a mold or into the final package. The other components are added to either of the two phases depending on the compatibility of the component with the phases. More phases can be utilized, if desired, by forming a separate solution of some of the components, with the separate phases then being added to either of the two main phases; or all of the phases could be poured together at the end, as, for example, with a multi-stream filling head or an in-line mixer.
PCT No. WO92/19221 discloses a process of forming an antiperspirant gel stick, including preparing a solution containing the gelling agent, a solvent for the gelling agent, and the gelling agent stabilizer; mixing an antiperspirant active into such solution; and cooling the solution to form a gel.
While, as seen in the foregoing, there has been a great deal of development work into forming antiperspirant sticks, including clear antiperspirant gel sticks, containing acidic antiperspirant active ingredients and gelled with a dibenzylidene sorbitol, it is still desired to provide a clear stick composition containing an acidic antiperspirant active ingredient and gelled with dibenzylidene sorbitol, which has increased stability over extended periods of times and wherein deterioration of the gelling agent, and production of benzaldehyde and formaldehydes due to such deterioration, are reduced. It is also still desired to provide such clear antiperspirant sticks wherein manufacture of the sticks is simplified.
U.S. Pat. No. 3,934,004 to Orren discloses antiperspirant compositions for topical application, containing selected reducing agents to prevent the formation of stains in soiled garments. This patent discloses that the stain resulting from the use of aluminum salt antiperspirant compositions can be reduced by either incorporating into the antiperspirant composition, or by applying to the affected areas of the garments immediately prior to washing of the garments, specified reducing agents which act to prevent the development of an antiperspirant yellow stain during subsequent cleaning of the garments. This patent discloses that the useful reducing agents include both organic and inorganic reducing agents which are water soluble (or water dispersible) and are cosmetically acceptable (that is, they are non-staining, non-irritating to the skin, and essentially odorless). Suitable reducing agents having these properties include a number of organic and inorganic sulphur-or phosphorous-containing compounds, as well as a number of stannous or titanous salts which may be either organic or inorganic. Suitable inorganic sulphur-containing reducing agents include various sulfites, bisulfites, hydrosulfites, metabisulfites, and thiosulfates. Useful organic sulphur-containing reducing agents include organic salts, such as organic bisulfites, in which the bisulfite group has replaced the hydrogen atom of an amino group, including monoethanolamine bisulfite, urea bisulfite, guanidine bisulfite, ethylaminebisulfite, and ethylenediamine bisulfite as well as higher linear and branched chain homologs and polymers thereof; and adducts of sulphur dioxide which are addition products formed between low molecular weight aldehydes or ketones and sodium or zinc bisulfite. This patent goes on to state that the antiperspirant compositions may be prepared in known forms such as emulsions, suspensions, creams, lotions and the like; and that these compositions also contain the usual auxiliary ingredients such as fillers, perfumes and surfactants.
U.S. Pat. No. 3,934,004 to Orren does not specifically disclose antiperspirant stick compositions, does not disclose clear antiperspirant stick compositions, and does not disclose that the reducing agent has an effect on, e.g., stability of the stick composition over extended periods of time.
U.S. Pat. No. 4,246,285 to Van Duzee discloses skin conditioning compositions, in the form of lotions, creams, solutions, gels and solids, containing guanidine inorganic salts, the compositions consisting essentially of the guanidine inorganic salts and a cosmetically acceptable vehicle capable of delivering the guanidine to the skin. This patent discloses that the guanidine inorganic salt, which can be guanidine carbonate, guanidine hydrochloride, guanidine bisulfite, guanidine sulfate, guanidine phosphate and/or guanidine hydrobromide, provides a skin conditioning benefit.
U.S. Pat. No. 4,246,285 does not disclose any effect of the guanidine compounds on stability of the disclosed skin conditioning compositions including the solid-form compositions. This patent is not concerned with an antiperspirant gel stick composition, or such composition that is clear.
Accordingly, it is still desired to provide stable, clear, antiperspirant solid gel stick compositions, containing an acidic astringent (antiperspirant) active and gelled with dibenzylidene sorbitol, which is stable over extended periods of time, and wherein the dibenzylidene sorbitol gelling agent does not deteriorate over extended periods of time.